The present invention relates to an absorption refrigerator. More particularly, the invention relates to an absorption refrigerator combined with a fluid concentrating boiler in the form of one body for a steam type double-effect absorption refrigerator of so-called reverse cycle type and parallel cycle type. Here, it is to be understood that the absorption refrigerator includes an absorption water cooling/heating device.
Conventionally, an apparatus as shown in FIG. 11 has been well known as a steam type double-effect absorption refrigerator. Such apparatus forms a reverse cycle in which an absorption fluid is fed to a high-temperature regenerator e from an absorber a through a low-temperature regenerator c. The absorption cycle in the apparatus is here described.
First, an absorption fluid (rare absorption fluid) lowered in concentration by absorbing a large volume of refrigerant steam in the absorber a is fed from the absorber a to a low-temperature heat exchanger b, in which the rare absorption fluid is heated by the low-temperature heat exchanger b, and then the absorption fluid is fed to the low-temperature regenerator c. The rare absorption fluid is regenerated under low-temperature at the low-temperature regenerator c and discharges a part of the absorbed refrigerant, resulting in increasing in concentration to become an absorption fluid of intermediate concentration (intermediate absorption fluid). Next, the intermediate absorption fluid is fed from the low-temperature regenerator c to the high-temperature heat exchanger d, in which the absorption fluid is heated by the high-temperature heat exchanger d, and then the absorption fluid is fed to the high-temperature regenerator e.
The intermediate absorption fluid is regenerated under high-temperature at the high-temperature regenerator e and discharges a part of the absorbed refrigerant, further increasing in concentration to become an absorption fluid of high concentration (concentrated absorption fluid). And, the concentrated absorption fluid is returned, as a heating source for heating the intermediate absorption fluid, to the heating side of the high-temperature heat exchanger d, and further returned, as a heating source for heating the rare absorption fluid, to the heating side of the low-temperature heat exchanger b, and then returned to the absorber a. The returned concentrated absorption fluid is sprayed at the absorber a and, while being cooled by cooling water, again absorbs the refrigerant steam to become the rare absorption fluid.
In FIG. 11, the marks f and g represent for a steam boiler and a condenser respectively.
Also, conventionally, an apparatus as shown in FIG. 12 has been well known as a steam type double-effect absorption refrigerator. Such apparatus forms a parallel cycle in which an absorption fluid is parallel-fed from an absorber a to both of low-temperature regenerator c and high-temperature regenerator e. The circulation cycle in the apparatus is described in the following.
First, an absorption fluid (rare absorption fluid) lowered in concentration by absorbing a large volume of refrigerant steam in the absorber a is fed from the absorber a to the low-temperature heat exchanger b, and the rare absorption fluid, after being heated by the low-temperature heat exchanger b, is branched into two directions. One of the branched fluid is fed to the low-temperature regenerator c via a medium-temperature heat exchanger h and is regenerated under low-temperature at the low-temperature regenerator c, and then returned to the heating side of low-temperature heat exchanger b via the heating side of medium-temperature heat exchanger d. The other fluid is fed to the high-temperature regenerator e via the high-temperature heat exchanger d, the fluid is regenerated under high-temperature at the high-temperature regenerator e, and then returned to the low-temperature heat exchanger b via the heating side of the high-temperature heat exchanger d.
The absorption fluid increased in concentration by discharging a part of the refrigerant absorbed by regeneration at the low-temperature regenerator c and high-temperature regenerator e are joined together before being fed to the low-temperature heat exchanger b, and the absorption fluid is passed to the heating side of low-temperature heat exchanger b, and then returned to the absorber a. The returned concentrated absorption fluid is sprayed at the absorber a and, while being cooled by cooling water, again absorbs the refrigerant steam to become the rare absorption fluid.
In such steam type double-effect absorption refrigerators of reverse cycle type and parallel cycle type, a high-temperature steam is fed as a heating source from the steam boiler f to the high-temperature regenerator e, and the intermediate absorption fluid is heated by the steam and discharges the absorbed refrigerant, and the discharged refrigerant steam is used as a heating source at the low-temperature regenerator c, and then returned to the condenser g to be condensed.
However, such steam type double-effect absorption refrigerator combined with the steam boiler f involves the following problems.
The steam boiler f itself is very large in size and makes the absorption refrigerator large-sized as a whole. Further, for the operation of the steam boiler f it is necessary to install separate systems for water feed, recovery of after-heating steam drain, injection of chemicals, etc. besides the absorption refrigerator. This contradicts the energy saving concept and further gives rise to getting larger in size of the refrigeration system as stated above since additional equipment is required therefor. Nevertheless, the role played by the steam boiler f for the absorption refrigerator is only feeding of the heating source and it is hard to say that the resultant effect is commensurate with the fuel consumed for the combustion at the steam boiler f. In addition, it is necessary to have qualified persons and to receive inspections, etc. for the operation of the boiler in accordance with the law.
The present invention has been made in order to solve these problems of the prior art, and the object of the invention is to provide an absorption refrigerator capable of achieving the reduction of the fuel consumption per cooling output and energy saving by using the boiler function fully, and further to provide a compact absorption refrigerator in total with easy operation.
The first aspect of the absorption refrigerator of the present invention is an absorption refrigerator which circulates absorption fluid from an absorber, through a low-temperature heat exchanger, a low-temperature regenerator, a high-temperature heat exchanger, a steam heating type high-temperature regenerator, the high-temperature heat exchanger and the low-temperature heat exchanger in order, back to the absorber comprising:
a fluid concentrating boiler which is disposed between the high-temperature regenerator and the high-temperature heat exchanger concentrating the absorption fluid under heat, and a feed means which extracts a part or all of the concentrated absorption fluid from the high-temperature regenerator and feeds it to the fluid concentrating boiler,
wherein the fluid concentrating boiler is connected to the high-temperature heat exchanger so that the absorption fluid concentrated under heat is returned to the heating side of the high-temperature heat exchanger and is also connected to the high-temperature regenerator so that refrigerant steam generated from the absorption fluid at the fluid concentrating boiler is fed as a heating source to the high-temperature regenerator.
The second aspect of the absorption refrigerator of the present invention is an absorption refrigerator in which absorption fluid, first fed from an absorber to a low-temperature heat exchanger, is branched into two passages, one leading to a low-temperature regenerator via a medium-temperature heat exchanger and the other leading to a steam heating type high-temperature regenerator via a high-temperature heat exchanger, and the absorption fluid regenerated at the low-temperature regenerator is returned to the heating side of the medium-temperature heat exchanger, while the absorption fluid regenerated at the high-temperature regenerator is returned to the heating side of the high-temperature heat exchanger, and these absorption fluid from the medium-temperature heat exchanger and the high-temperature heat exchanger are joined together and returned to the absorber through the heating side of the low-temperature heat exchanger comprising:
a fluid concentrating boiler which is disposed between the high-temperature regenerator and the high-temperature heat exchanger and concentrates the absorption fluid under heat, and a feed means which extracts a part or all of the concentrated absorption fluid from the high-temperature regenerator and feeds same to the fluid concentrating boiler,
wherein the fluid concentrating boiler is connected to the high-temperature heat exchanger so that the absorption fluid concentrated under heat is returned to the heating side of the high-temperature heat exchanger and is also connected to the high-temperature regenerator so that refrigerant steam generated from the absorption fluid at the fluid concentrating boiler is fed as a heating source to the high-temperature regenerator.
The third aspect of the absorption refrigerator of the present invention is an absorption refrigerator in which absorption fluid, first fed from an absorber to a low-temperature heat exchanger, is branched into two passages, one leading to a low-temperature regenerator and the other leading to a steam heating type high-temperature regenerator via a high-temperature heat exchanger, and the absorption fluid regenerated at the low-temperature regenerator and the absorption fluid regenerated at the high-temperature regenerator and passed through the high-temperature heat exchanger are joined together and returned to the absorber through the heating side of the low-temperature heat exchanger comprising:
a fluid concentrating boiler which is disposed between the high-temperature regenerator and the high-temperature heat exchanger and concentrates the absorption fluid under heat, and a feed means which extracts a part or all of the concentrated absorption fluid from the high-temperature regenerator and feeds same to the fluid concentrating boiler,
wherein the fluid concentrating boiler is connected to the high-temperature heat exchanger so that the absorption fluid concentrated under heat is returned to the heating side of the high-temperature heat exchanger and is also connected to the high-temperature regenerator so that refrigerant steam generated from the absorption fluid at the fluid concentrating boiler is fed as a heating source to the high-temperature regenerator.
In the absorption refrigerator of the present invention, it is possible to comprise a first heat exchanger of which heating source is a return absorption fluid returned from the outlet side of the fluid concentrating boiler to the high-temperature heat exchanger,
wherein a feed absorption fluid fed from the high-temperature regenerator undergoes heat exchange with the return absorption fluid at the first heat exchanger before being fed to the fluid concentrating boiler.
Further, in the absorption refrigerator of the present invention, it is possible to comprise a second heat exchanger of which heating source is the combustion exhaust gas of the fluid concentrating boiler,
wherein the feed absorption fluid fed from the high-temperature regenerator undergoes heat exchange with the combustion exhaust gas at the second heat exchanger before being fed to the fluid concentrating boiler.
Still further, in the absorption refrigerator of the present invention, it is possible that the second heat exchanger is an economizer applied to the fluid concentrating boiler, and that the feed absorption fluid is heated by the economizer.
Still further, in the absorption refrigerator of the first aspect of the present invention, it is possible that an auxiliary regenerator of which heating source is the combustion exhaust gas of the fluid concentrating boiler is disposed at the inlet side of the absorption fluid to the low-temperature regenerator in the range from the low-temperature heat exchanger to the low-temperature regenerator, and/or at the inlet side of the absorption fluid to the high-temperature regenerator in the range from the high-temperature heat exchanger to the high-temperature regenerator; in the absorption refrigerator of the second aspect of the present invention, it is possible that an auxiliary regenerator of which heating source is the combustion exhaust gas of the fluid concentrating boiler is disposed at the inlet side of the absorption fluid to the low-temperature regenerator in the range from the medium-temperature heat exchanger to the low-temperature regenerator, and/or at the inlet side of the absorption fluid to the high-temperature regenerator in the range from the high-temperature heat exchanger to the high-temperature regenerator; in the absorption refrigerator of the third aspect of the present invention, it is possible that an auxiliary regenerator of which heating source is the combustion exhaust gas of the fluid concentrating boiler is disposed at the inlet side of the absorption fluid to the low-temperature regenerator in the range from the absorption fluid branch point to the low-temperature regenerator, and/or at the inlet side of the absorption fluid to the high-temperature regenerator in the range from the high-temperature heat exchanger to the high-temperature regenerator.
Still further, in the absorption refrigerator of the present invention, it is possible that a third heat exchanger that heats rare absorption fluid by using the refrigerant drain of the low-temperature regenerator as a heating source is disposed in parallel with the low-temperature heat exchanger or in series at the outlet side of the absorption fluid of the low-temperature heat exchanger.
Still further, in the absorption refrigerator of the present invention, it is possible that a fourth heat exchanger that heats intermediate absorption fluid by using as a heating source the refrigerant drain of the low-temperature regenerator is disposed in parallel with the high-temperature heat exchanger or in series at the outlet side of the absorption fluid of the high-temperature heat exchanger.
Still further, in the absorption refrigerator of the first aspect of the present invention, it is possible that a part of the absorption fluid is bypassed from the upstream side of an intermediate fluid feed means to a absorption fluid return line between the high-temperature heat exchanger and the low-temperature heat exchanger.
Still further, in the absorption refrigerator of the present invention, it is possible to provide a plurality of combinations of absorber and generator, wherein cold water, cooling water and absorption fluid are series-fed to the plurality of combinations; or it is possible to provide a plurality of combinations of absorber and generator, wherein cold water and absorption fluid are series-fed to the plurality of combinations and further cooling water is parallel-fed to the plurality of combinations.
Still further, in the absorption refrigerator of the present invention, it is possible that cooling water is fed from the condenser to the absorber.
Still further, in the absorption refrigerator of the present invention, it is preferable that the fluid concentrating boiler is a once-through boiler.
The absorption refrigerator of the invention has a configuration as described above and is in no need of providing any particular water feeding system for the boiler and requires no recovery of steam drain. Also, it is not necessary to have a chemical injection device, enabling the miniaturization of the boiler. Consequently, the boiler can be integrated into the absorption refrigerator.